<?php
class MysqlDb
{
    private $_host; //主机地址
    private $_user; //用户名
    private $_pwd; //密码
    private $_db; //数据库
    private $_char; //字符集
    private $_link; //连接
    //构造

    private static $_instance;
    private function __construct($config = array())
    {
        $this->_init($config);
        $this->_connect();
        $this->_charset();
        $this->_dbset();
    }
    public static function getInstance()
    {
        if (is_null(static::$_instance) || !is_object(static::$_instance)) {
            static::$_instance = new MysqlDb();
        }
        return static::$_instance;
    }
    private function __clone()
    {

    }




    //初始化属性
    private function _init($config = array())
    {
        $this->_host = isset($config['host']) ? $config['host'] : 'localhost';
        $this->_user = isset($config['user']) ? $config['user'] : 'root';
        $this->_pwd  = isset($config['pwd']) ? $config['pwd'] : 'root';
        $this->_db   = isset($config['db']) ? $config['db'] : 'football';
        $this->_char = isset($config['char']) ? $config['char'] : 'utf8';
    }
    //连接
    private function _connect()
    {
        $link = @mysql_connect($this->_host, $this->_user, $this->_pwd);
        if ($link) {
            $this->_link = $link;
        } else {
            die('数据库连接失败，失败原因：' . mysql_error());
        }
    }
    //设置字符集
    private function _charset()
    {
        mysql_set_charset($this->_char);
    }
    //选择数据库
    private function _dbset()
    {
        mysql_select_db($this->_db);
    }
    //query
    public function query($sql)
    {
        $res    = mysql_query($sql);
        $return = array();
        // var_dump($res);
        if ($res) {
            while ($row = mysql_fetch_assoc($res)) {
                $return[] = $row;
            }
            mysql_free_result($res);
            return $return;
        } else {
            die('查询sql有误，语句为' . $sql . '错误原因：' . mysql_error());
        }
    }
    //exec
    public function exec($sql)
    {
        $res = mysql_query($sql);
        if ($res) {
            return mysql_affected_rows();
        } else {
            die('增删改sql有误，语句为' . $sql . '错误原因：' . mysql_error());
        }
    }
    //关闭数据库
    public function __destruct()
    {
        mysql_close();
    }
}
